Measurement of those areas is required in order to accurately diagnose neurological, psychological, cognitive, and psychiatric disorders and to design effective treatment and intervention plans. Treatment and service recommendations depend on good diagnosis, and diagnosis is only as good as the assessment data that informs it.

Objective data is obtained through neuropsychological assessment and testing.

Cognitive functions, or "thinking abilities," as well as personality characteristics, psychiatric symptoms, and psychological adjustment are objectively and non-invasively measured with standardized, valid and reliable, psychometrically sound, paper and pencil tests.

Some examples of "thinking abilities" include, but are not limited to: